Air-conditioning control apparatus and method

ABSTRACT

[Problem] 
     Accurately to detect the presence or absence of a person even when a background temperature rises near the surface temperature of a person. 
     [Solving Means] 
     Equipped with a background-temperature calculation unit that calculates a background temperature that relates to a background temperature that is a background temperature of a person from thermal images, an air-conditioning control unit compares a judgment temperature Tj for judging whether it is necessary to start forced cooling in the room RM and a background temperature Tb obtained by the background-temperature calculation unit, and starts forced cooling to lower the background temperature Tb at the point when the background temperature Tb is above the judgment temperature Tj (Tb&gt;Tj).

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to Japanese Patent Application No. 2014-177720, filed on Sep. 2, 2014, the entire contents of which are incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to air-conditioning technology, and more particularly to air-conditioning technology for controlling air-conditioning of a room in response to a position of a person in the room detected by a thermopile sensor array.

BACKGROUND ART

So-called central air-conditioning was typical for controlling a large building, such as an office building or the like to be a comfortable air-conditioned environment anywhere and at any time regardless of whether a person is present in a room. However, in recent years, the orientation toward energy conservation has strengthened, so there is a trend to introduce air-conditioning technology that implements energy conservation by detecting a position of a person in a room, and stopping air-conditioning or lighting in areas where there is no one in the room.

Conventionally, a technology has been proposed for this kind of air-conditioning control technology that detects a thermal image (thermography) in a room using a plurality of infrared ray sensors attached to a wall or a ceiling, for example, and that senses that a person is in the room by searching for a person region indicating a surface temperature of a person from the obtained thermal images, to stop the air-conditioning or the lighting in rooms or areas where no one is in the room, by limiting control for a comfortable, air-conditioned environment to rooms and areas where a person is present.

PRIOR ART DOCUMENT Patent Document

[Patent Document 1]

Unexamined Patent Application Publication 2012-057840

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

However, with this kind of conventional technology, a person in the room is sensed by searching for a person region that indicates the surface temperature of a person from thermal images of the room detected by temperature sensors. For that reason, if a background temperature, specifically a temperature of a floor or a ceiling in a background of a person in the thermal image, is near the surface temperature of the person, there is a problem in that it is not possible to clearly distinguish between the background and the person in the room. Particularly, the temperature of the floor and walls near a window easily rises in the summer. Although rare, there are cases where the temperature rises to the same degree as the surface temperature of a person. Therefore, in a circumstance where the background temperature rises in this way, it is not possible to implement appropriate air-conditioning control that corresponds to whether a person is in a room or to their position.

At this time, the overall cost of the air-conditioning control system can be reduced if a thermopile array sensor is used as the temperature sensor because the sensor itself is inexpensive, but pixels that compose the obtained thermal image are rough, and there is much noise so the accuracy of detecting a person drops. Therefore, in a circumstance where the background temperature rises, it is even more difficult to distinguish between the background and a person in the room, making it impossible to accurately detect a person in the room.

Conversely, if a presently mainstream micro bolometer-type infrared thermometer is used as the temperature sensor that detects thermal images, it is possible to obtain thermal images with a high resolution and low noise but the cost of the infrared thermometer itself is high so it is not possible to avoid a cost increase. Also, the frequency at which such a circumstance occurs in one year is extremely low, so it is inefficient to incur the costs to support such rare cases.

The present invention was created to address these problems. An object of the present invention is to provide an air-conditioning technology that accurately detects whether a person is in a room even when the background temperature rises to near the surface temperature of a person.

Means for Solving the Problem

To attain such an object, the air-conditioning apparatus pursuant to the present invention is equipped with a person-detection unit that detects the presence or absence of a person in a room based on thermal image data generated from data outputted from temperature sensors disposed in a room that is targeted for control, and a background-temperature calculation unit that calculates the background temperature that relates to the background of a person from the thermal images, wherein the air-conditioning control unit compares a judgment temperature for judging whether it is necessary to start forced cooling in the room and the background temperature, and starts forced cooling to lower the background temperature at the point when the background temperature is higher than the judgment temperature.

Also, in one constitution example of the air-conditioning control apparatus pursuant to the present invention, the person-detection unit includes a low-precision person detection function that searches for a person region that indicates the surface temperature of a person from the thermal images, and detects the presence or absence of a person based on the search result, and a high-precision person detection function that detects the presence or absence of a person based on the presence or absence of movement in the person region searched in each of the thermal images accumulated in time series. The air-conditioning control apparatus starts forced cooling at a point when the existence of a person is detected by the high-precision person detection function, instructing the person-detection unit to switch to the high-precision person detection function at a point when the background temperature is higher than the judgment temperature.

Also, in the constitution example of the air-conditioning control unit according to the present invention, the air-conditioning control unit starts forced cooling when the background temperature is higher than the judgment temperature, and it is also notified from outside that a person has entered the room.

Again, in a constitution example of the air-conditioning apparatus according to the present invention, the air-conditioning control unit constantly implements partial cooling to lower the background temperature near the entrance of the room, and starts forced cooling at the point when the existence of a person is detected by the person-detection unit near the entrance.

Also, in a constitution example of the air-conditioning control unit according to the present invention, the air-conditioning control unit does partial cooling of a region where the background temperature in a room is higher than the judgment temperature as forced cooling.

Also, an air-conditioning method pursuant to the present invention includes a person-detection step that detects the presence or absence of a person in a room based on thermal images of the room detected by temperature sensors disposed in the room targeted for control; an air-conditioning control step that controls air-conditioning of the room based on the detection results obtained with the person-detection step; and a background temperature calculation step that calculates the background temperature that relates to the background of a person from the thermal images, wherein the air-conditioning control step compares a judgment temperature for judging whether it is necessary to start forced cooling in the room and the background temperature, and starts forced cooling to lower the background temperature at the point when the background temperature is higher than the judgment temperature.

Effect of the Invention

Pursuant to the present invention, at a point when the background temperature rises above a judgment temperature, and differentiation of both becomes difficult, forced cooling is automatically started to lower the background temperature. Therefore, even when the background temperature rises to near the surface temperature of the person, the background temperature is forcibly lowered by the cooler, so it becomes easier to distinguish between both, and it is possible to accurately detect whether a person is in the room and to detect the person's position. For that reason, as a result, it is possible to implement an optimal air-conditioning control that corresponds to whether there is a person in the room and to their position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a constitution of an air-conditioning control apparatus pursuant to a first embodiment of the present invention;

FIG. 2 is a flowchart showing a forced cooling necessity-judgment process pursuant to the first embodiment of the present invention;

FIG. 3 is a timing chart showing the forced cooling necessity-judgment process pursuant to the first embodiment of the present invention;

FIG. 4 is an example of a thermal image when a background temperature rises;

FIG. 5 is an example of a thermal image after the background temperature is lowered by forced cooling;

FIG. 6 is a flowchart showing a forced cooling necessity-judgment process pursuant to a second embodiment of the present invention;

FIG. 7 is a timing chart showing the forced cooling necessity-judgment process pursuant to the second embodiment of the present invention;

FIG. 8 is a flowchart showing a forced cooling necessity-judgment process pursuant to a third embodiment of the present invention;

FIG. 9 is a timing chart showing the forced cooling necessity-judgment process pursuant to the third embodiment of the present invention;

FIG. 10 is a flowchart showing a forced cooling necessity-judgment process pursuant to a fourth embodiment of the present invention; and

FIG. 11 is a timing chart showing the forced cooling necessity-judgment process pursuant to the fourth embodiment of the present invention;

MODES FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will now be described with reference to the drawings.

[First Embodiment]

Initially, an air-conditioning control apparatus 10 pursuant to a first embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a block diagram of a constitution of an air-conditioning control apparatus pursuant to the first embodiment of the present invention.

Overall, the air-conditioning control apparatus 10 is composed of information processing devices such a server device, a personal computer, and an industrial controller and the like, and the apparatus has a person-detection function that detects the presence or absence of a person in a room RM based on a thermal image (thermography) of the room RM generated from data outputted from a temperature sensor arranged in the room RM that is targeted for control, to control the air-conditioning of the room RM based on the obtained person-detection output, and further to control equipment and devices such as lighting fixtures disposed in the room RM.

The present invention, when the background temperature relating to the background region of a floor or a wall in the background of a person rises, and it is difficult to distinguish from the surface temperature of a person, lowers the background temperature by forcibly cooling the room RM to make it easier to distinguish from a person's surface temperature from among thermal images used with this kind of person-detection function.

As main functional units, a thermal-image generation unit 11, a person-detection unit 12, a background-temperature calculation unit 13, and an air-conditioning control unit 14 are disposed in the air-condition control apparatus 10.

The thermal-image generation unit 11 is connected via a communication line L1 to temperature sensors S1 and S2 such as a thermopile array sensor or the like disposed in a ceiling or a wall of each area A1 and A2 in the room RM, and has the function of generating thermal images of the entire region of the room RM by obtaining and combining data outputted from these temperature sensors S1 and S2.

The person-detection unit 12 has the function of detecting the presence of a person or their position in the room RM by searching for a person region that indicates the surface temperature of a person which is higher than the background temperature that relates to the background region of the floor or the walls in the background of the person from the thermal images generated by the thermal-image generation unit 11.

The background-temperature calculation unit 13 has the function of calculating the background temperature relating to the background region of the floor or the wall in the background of the person of the thermal images, using statistical processing such as averaging or calculation of a representative value for each pixel value that composes the thermal images, for the thermal images generated by the thermal-image generation unit 11.

With regard to a specific calculation method of the background temperature, it is acceptable, for example, to find the background temperature by implementing statistical processing using the pixel values of all regions constituting the thermal images as the target. When doing so, it is acceptable to find the background temperature by implementing a statistical processing for only pixel values that exclude the pixel values that belong to a heat-generating body region where a heat-generating body exists such as a person region or an electronic device or the like, from pixel values that are targeted for the statistical processing. Also, when a specific temperature-rise region is fixed, where a temperature rise occurs, such as near a window or the like, it is acceptable to find the background temperature by implementing statistical processing targeting only the pixel values that belong to this temperature-rise region.

In addition to the typical air-conditioning control functions that control air-conditioners 21, 22, 23, and 24 disposed in a ceiling of each area A1 and A2, or air-conditioning equipment 20 that supplies air-conditioning air to these air-conditioners, by remote control via the communication line L2, in response to measurement input of the room temperature of each area A1 and A2, or the outside air temperature or the like, or in response to operational input from an operator, the air-conditioning control unit 14 has a function of doing remote control via a communication line L3 of the presence or absence of air-conditioning control for each area A1 and A2, and the presence or absence of driving of equipment and devices such as lighting fixtures 31 and 32 or the like disposed in each area A1 and A2 in response to person-detection output from the person-detection unit 12.

Also, as a support function for the characteristic person detection pursuant to this embodiment of the present invention, the air-conditioning control unit 14 has the function of giving instructions via the communication line L2 to the air-conditioners 21, 22, 23, and 24, and also air-conditioning equipment 20 to start forced cooling to lower the background temperature Tb at a point when the background temperature Tb is above a judgment temperature Tj (Tb>Tj) by comparing the judgment temperature Tj for judging whether it is necessary to start forced cooling of the room RM, and the background temperature Tb obtained by the background-temperature calculation unit 13.

[Operation of the First Embodiment]

Next, the operation of the air-conditioning control apparatus 10 pursuant to this embodiment of the present invention will be described with reference to FIGS. 2 and 3. FIG. 2 is a flowchart showing a forced cooling necessity-judgment process pursuant to the first embodiment of the present invention. FIG. 3 is a timing chart showing the forced cooling necessity-judgment process pursuant to the first embodiment of the present invention.

The air-conditioning control apparatus 10 generates thermal images using the thermal-image generation unit 11 by periodically obtaining data outputted from the temperature sensors S1 and S2, and executes the forced cooling necessity-judgment process depicted in FIG. 2 to support the person-detection operation in the person-detection unit 12.

Initially, the background-temperature calculation unit 13 obtains thermal images from the thermal-image generation unit 11 (step 100), to calculate the background temperature Tb that relates to the background region of the floor or a wall in the background of the person by implementing statistical processing of the pixel values that constitute the thermal images (step 101).

Next, the air-conditioning control unit 14 compares the background temperature Tb calculated by the background-temperature calculation unit 13, and the preset judgment temperature Tj used for judging whether it is necessary to start forced cooling of the room RM (step 102).

Here, when the background temperature Tb is higher than the judgment temperature Tj, specifically Tb>Tj (step 102: YES), the air-conditioning control unit 14 gives instructions via the communication line L2 to the air conditioners 21, 22, 23, and 24, and the air-conditioning equipment 20 to start forced cooling to lower the background temperature Tb (step 103), and ends the series of forced cooling necessity-judgment processes.

Conversely, when the background temperature Tb is equal to or lower than the judgment temperature Tj, specifically Tb≦Tj (step 102: NO), the air-conditioning control unit 14 ends the series of forced cooling necessity-judgment processes without instructing to start forced cooling.

Therefore, as shown in FIG. 3, at the point when the background temperature Tb is greater than the judgment temperature Tj, forced cooling is started for the room RM at a time t0. For that reason, the floor or the wall in the room RM is cooled by the forced cooling, and the background temperature Tb drops below the judgment temperature TJ at a time t1 thereafter. With this, the temperature difference between the background temperature and the surface temperature of a person is adequately large, so it is possible to accurately detect the presence of a person in the room because it is easier to differentiate between both.

At this time, as a specific example of forced cooling, there is a method to preset a forced cooling target temperature at a fixed temperature from the surface temperature of a person, for example, and to change the settings of the target temperature of the room RM when executing forced cooling to the forced-cooling target temperature. It is acceptable to determine this forced-cooling target temperature based on parameters such as variations in measurement values of the temperature sensors S1 and S2, temperature change speeds of the floor of the wall in the room RM, and permissible time until it is possible to accurately detect a person.

Also, with regard to quitting forced cooling, it is acceptable for the air-conditioning control unit 14 to compare the background temperature Tb and a preset forced cooling stop temperature Ts, for example, and to instruct the air-conditioners 21, 22, 23, and 24, and the air-conditioning equipment 20 to stop forced cooling at a point when Tb is at or below Ts (Tb≦Ts).

FIG. 4 is an example of a thermal image when a background temperature rises. FIG. 5 is an example of a thermal image after the background temperature is lowered by the forced cooling. In FIGS. 4, and 5, a rectangular room RM targeted for control is separated into eight, 2×4 zones A1-A8, and temperature sensors S1-S8 are disposed in the center portion of a ceiling of these zones. Thermal images of each zone A1-A8 generated from data outputted from these temperature sensors S1-S8 are combined into one.

With the thermal image example depicted in FIG. 4, a temperature rise is found near a window disposed in a wall face in zones A1 and A2, indicating a background temperature that is the same or higher than a person region positioned in the center of the room RM. In such a circumstance, if forced cooling is started, the thermal images will change as shown in FIG. 5. It can be seen that the background temperature near the window has dropped below that of the person region. With this, it is possible easily to differentiate between the background temperature and the person region.

[Effect of the First Embodiment]

In this way, equipped with the background-temperature calculation unit 13 that calculates the background region that relates to the background of a person from thermal images, the air-conditioning control unit 14 compares the judgment temperature Tj for judging whether it is necessary to start forced cooling in the room RM and the background temperature Tb obtained by the background-temperature calculation unit 13, and starts forced cooling to lower the background temperature Tb at the point when the background temperature Tb is higher than the judgment temperature Tj (Tb>Tj).

With this, forced cooling is automatically started at the point when it is difficult to differentiate between both because the background temperature Tb is higher than the judgment temperature Tj, so the background temperature Tb is lowered. Therefore, even when the background temperature Tb rises to near the surface temperature of person, the background temperature Tb is forcibly lowered by the cooler, so it becomes easier to distinguish between both, and it is possible to accurately detect whether a person is in the room and the person's position. For that reason, as a result, it is possible to implement an optimal air-conditioning control that corresponds to whether there is a person in the room and to their position.

[Second Embodiment]

Next, the air-conditioning control apparatus 10 pursuant to a second embodiment of the present invention will be described with reference to FIGS. 6, and 7. FIG. 6 is a flowchart showing the forced cooling necessity-judgment process pursuant to the second embodiment of the present invention; FIG. 7 is a timing chart showing the forced cooling necessity-judgment process pursuant to the second embodiment of the present invention.

With the first embodiment, an example was used to describe starting forced cooling to lower the background temperature Tb at the point when the background temperature Tb is higher than the judgment temperature Tj (Tb>Tj). With this embodiment, an example is described that instructs the person-detection unit 12 to switch to a high-precision person-detection process at a point when Tb is greater than Tj, to start forced cooling at a point when a person is detected to be in the room by the high-precision person-detection process.

In this embodiment, the person-detection unit 12 has a low-precision person detection function that searches for a person region that indicates the surface temperature of the person from the thermal images, and detects the presence of a person based on the search result, and a high-precision person detection function that detects the presence of a person based on the presence or absence of movement in the person region searched in each of the thermal images accumulated in time series. For example, in the event that there is movement in the person region in one second of time, and it is judged that a person is present, thermal images generated every 0.1 seconds are accumulated in 10 image groups in the thermal-image generation unit 11. If the center position of the person region is calculated for each of these thermal images, it is possible to determine the existence or non-existence of movement in the person region every one second.

The air-conditioning control unit 14 has a function of instructing to switch to the high-precision person detection function for the person-detection unit 12 instead of the instruction to start forced cooling at the point when the background temperature Tb is higher than the judgment temperature Tj, and a function of starting forced cooling at the point when it is detected that a person is in the room by the high-precision person detection function.

[Operation of the Second Embodiment]

Next, the operation of the air-conditioning control apparatus 10 pursuant to the second embodiment of the present invention will be described with reference to FIGS. 6 and 7.

The air-conditioning control apparatus 10 generates thermal images using the thermal-image generation unit 11 by periodically obtaining data outputted from the temperature sensors S1 and S2, and executes the forced cooling necessity-judgment process depicted in FIG. 6 to support the person-detection operation in the person-detection unit 12.

Initially, the background-temperature calculation unit 13 obtains thermal images from the thermal-image generation unit 11 (step 200) to calculate the background temperature Tb that relates to the background region of the floor or a wall in the background of the person, by implementing statistical processing of values of the pixels that constitute the thermal images (step 201).

Next, the air-conditioning control unit 14 compares the background temperature Tb calculated by the background-temperature calculation unit 13 and the preset judgment temperature Tj used for judging whether it is necessary to start forced cooling of the room RM (step 202).

Here, when the background temperature Tb is higher than the judgment temperature Tj, specifically Tb>Tj (step 202: YES), the air-conditioning control unit 14 instructs the person-detection unit 12 to switch to the high-position person detection function (step 203).

With this, the person-detection unit 12 uses the high-precision person detection function for the thermal images obtained from the thermal-image generation unit 11 to detect the presence or absence of a person based on the presence or absence of movement in the person regions searched from the thermal images accumulated in time series (step 204).

Here, when the existence of a person is detected (step 205: YES), the air-conditioning control unit 14 gives instructions via the communication line L2 to the air conditioners 21, 22, 23, and 24, and the air-conditioning equipment 20 to start forced cooling to lower the background temperature Tb (step 206), and ends the series of forced cooling necessity-judgment processes.

Conversely, when the background temperature Tb is the same or lower than the judgment temperature Tj, specifically Tb≦Tj at step 202 (step 202: NO), and the existence of a person is not detected at step 205 (step 205: NO), the air-conditioning control unit 14 ends the series of forced cooling necessity judgment processes, without instructing to start forced cooling.

Therefore, as shown in FIG. 7, at time t0, at the point when the background temperature Tb is greater than the judgment temperature Tj, the person-detection unit 12 is instructed to switch to the high-precision person detection function without starting forced cooling of the room RM, and at the subsequent time t1, when the existence of a person is confirmed by the high-precision person detection function, forced cooling is started for the room RM.

With this, at a time t2 thereafter, the floor or the wall in the room RM is cooled by the forced cooling, and the background temperature Tb drops below the judgment temperature TJ. Therefore, the temperature difference between the background temperature and the surface temperature of a person is adequately large in the thermal image, and it is possible to accurately detect the presence or absence of a person in the room because it is easier to differentiate between both.

[Effects of the Second Embodiment]

In the embodiment of the present invention described above, the air-conditioning control unit 14 instructs the person-detection unit 12 to switch to the high-precision person detection function at the point when the background temperature Tb is higher than the judgment temperature Tj, to start forced cooling at the point when the existence of a person is detected by the high-precision person detection function.

At this time, because the high-precision person detection function detects a person using a plurality of thermal images, though the time required for detection is longer compared to the low-precision person detection function, it is possible to accurately judge the presence or absence of a person when there is only a slight temperature difference of the background temperature Tb and the surface temperature of a person.

For that reason, when the background temperature Tb is higher than the judgment temperature Tj, forced air conditioning is started only after the point when the existence of a person has been confirmed. If the existence of a person has not been confirmed, the starting of forced air conditioning is not implemented. Therefore, as in the first embodiment, compared to when starting forced cooling at the point when the background temperature TB is higher than the judgment temperature Tj, it is possible to start forced air conditioning only when the existence of a person has been confirmed, thereby circumventing wastefully implementing forced air conditioning regardless of whether there is a person in the room RM.

[Third Embodiment]

Next, the air-conditioning control apparatus 10 pursuant to a third embodiment of the present invention will be described with reference to FIGS. 8 and 9. FIG. 8 is a flowchart showing a forced cooling necessity judgment process pursuant to the third embodiment of the present invention. FIG. 9 is a timing chart showing the forced cooling necessity judgment process pursuant to the third embodiment of the present invention.

With the first embodiment, an example of starting forced cooling to lower the background temperature Tb at the point when the background temperature Tb is higher than the judgment temperature Tj (Tb>Tj) was used for the explanation. With this embodiment, an example is described that starts forced cooling when Tb>Tj, and in addition, entry of a person into the room RM is notified from outside.

In this embodiment, it is presumed that the air-conditioning control apparatus 10 is notified from an entry-control system (not shown in the drawings) that controls entry of a person into the room RM. This entry-control system is a typical system for releasing an electric lock of an entry door in response to judgment of permission to enter by judging whether to allow entry of the person into the room RM based on user information read from the user's ID card at a card terminal disposed at the entry of the room RM, for example.

The air-conditioning control unit 14 has a function of starting forced cooling when the background temperature is higher than the judgment temperature, and it is also notified from outside that a person has entered the room RM.

[Operation of the Third Embodiment]

Next, the operation of the air-conditioning control apparatus 10 pursuant to this embodiment of the present invention will now be described with reference to FIGS. 8 and 9.

The air-conditioning control apparatus 10 generates thermal images using the thermal-image generation unit 11 by periodically obtaining data outputted from the temperature sensors S1 and S2, and executes the forced cooling necessity-judgment process depicted in FIG. 8 to support the person detection operation in the person-detection unit 12.

Initially, the background-temperature calculation unit 13 obtains thermal images from the thermal-image generation unit 11 (step 300) to calculate the background temperature Tb that relates to the background region of the floor or a wall in the background of the person, by implementing statistical processing of values of the pixels that constitute the thermal images (step 301).

Next, the air-conditioning control unit 14 compares the background temperature Tb calculated by the background-temperature calculation unit 13 and the preset judgment temperature Tj used for judging whether it is necessary to start forced cooling of the room RM (step 302).

Here, when the background temperature Tb is higher than the judgment temperature Tj, specifically Tb>Tj (step 302: YES), the air-conditioning control unit 14 confirms whether it has been notified of the entry of a person to the room RM from outside (step 303).

Here, when it has been notified of the entry of a person to the room RM from outside (step 303: YES), the air-conditioning control unit 14 gives instructions via the communication line L2 to the air conditioners 21, 22, 23, and 24, and the air-conditioning equipment 20 to start forced cooling to lower the background temperature Tb (step 304), and ends the series of forced cooling necessity-judgment processes.

Conversely, when the background temperature Tb is the same or lower than the judgment temperature Tj, specifically Tb≦Tj at step 302 (step 302: NO), and the entry of a person has not been notified at step 303 (step 303: NO), the air-conditioning control unit 14 ends a series of forced cooling necessity judgment processes without instructing to start forced cooling.

Therefore, as shown in FIG. 9, at the point when the background temperature Tb is greater than the judgment temperature Tj, at time t0, forced cooling of the room RM is not started, and at the subsequent time t1, when it has been notified that a person has entered the room RM from outside, forced cooling is started for the room RM.

With this, the floor or the wall in the room RM is cooled by the forced cooling, and the background temperature Tb drops below the judgment temperature Tj at a time t2 thereafter. Therefore, the temperature difference between the background temperature and the surface temperature of a person is adequately large in the thermal images, making it possible to accurately detect the presence or absence of a person in the room because it is easier to differentiate between both.

[Effects of the Third Embodiment]

In this way, with this embodiment, the air-conditioning control unit 14 starts forced cooling when the background temperature Tb is higher than the judgment temperature Tj, and it is also notified from outside that a person has entered the room RM.

For that reason, when the background temperature Tb is higher than the judgment temperature Tj, forced air conditioning is started only after the point when the existence of a person has been confirmed by external notification, and if the existence of the person could not be confirmed, the starting of forced cooling is not implemented. Therefore, as in the first embodiment, compared to when starting forced cooling at the point when the background temperature Tb is higher than the judgment temperature Tj, it is possible to start forced air conditioning only when the existence of a person has been confirmed, thereby circumventing wastefully implementing forced air conditioning regardless of whether there is a person in the room RM.

[Fourth Embodiment]

Next, the air-conditioning control apparatus 10 pursuant to a fourth embodiment of the present invention will now be described with reference to FIGS. 10 and 11. FIG. 10 is a flowchart showing a forced cooling necessity judgment process pursuant to the fourth embodiment of the present invention. FIG. 11 is a timing chart showing the forced cooling necessity-judgment process pursuant to the fourth embodiment of the present invention.

With the first embodiment, an example of starting forced cooling to lower the background temperature Tb at the point when the background temperature Tb is higher than the judgment temperature Tj (Tb>Tj) was used for the explanation. With this embodiment, we will describe a case when partial cooling is constantly performed to lower the background temperature near the room RM, and starting of forced cooling is implemented at the point when the existence of a person is detected near the entrance.

With this embodiment, the air-conditioning control unit 14 has a function of constantly performing partial cooling to lower the background temperature near the entrance of the room RM, and a function of starting forced cooling at the point when it is detected by the person-detection unit 12 that a person exists near the entrance.

[Operation of the Fourth Embodiment]

Next, the operation of the air-conditioning control apparatus 10 pursuant to this embodiment of the present invention will be described with reference to FIGS. 10 and 11.

The air-conditioning control apparatus 10 generates thermal images using the thermal-image generation unit 11 by periodically obtaining data outputted from the temperature sensors S1 and S2 executes the forced cooling necessity-judgment process depicted in FIG. 10 to support the person detection operation in the person-detection unit 12. At this time, the air-conditioning control unit 14 constantly implements partial cooling to lower the background temperature near the entrance of the room RM in advance.

Initially, the person-detection unit 12 detects the presence or absence of a person or their position in the room RM (step 401) by searching for a person region that indicates the surface temperature of the person, which is higher than the background temperature associated with the background region of the floor or the walls in the region near the entrance of the room RM, by obtaining thermal images (step 400) generated by the thermal-image generation unit 11.

In response to this, the air-conditioning control unit 14 confirms whether the existence of a person was detected near the entrance of the room RM, based on detection results obtained from the person-detection unit 12 (step 402).

Here, when the existence of a person is detected near the entrance of the room RM (step 402: YES), the air-conditioning control unit 14 gives instructions via the communication line L2 to the air conditioners 21, 22, 23, and 24, and the air-conditioning equipment 20 to start forced cooling to lower the background temperature Tb (step 403), and ends the series of forced cooling necessity-judgment processes.

Conversely, when the existence of a person was not detected near the entrance of the room RM (step 402: NO), the air-conditioning control unit 14 ends the series of forced cooling necessity-judgment processes, without instructing to start forced cooling.

Therefore, as shown in FIG. 11, at time t0, at the point when the presence of the person was detected near the entrance of the room RM, forced cooling of the room RM is started.

With this, the floor or the wall in the room RM is cooled by the forced cooling, and the background temperature Tb drops below the judgment temperature Tj at a time t1 thereafter. Therefore, the temperature difference between the background temperature and the surface temperature of a person is adequately large in the thermal images, making it possible to accurately detect the presence or absence of a person in the room because it is easier to differentiate between both.

[Effects of the Fourth Embodiment]

With this embodiment, the air-conditioning control unit 14 constantly implements partial cooling to lower the background temperature near the entrance of the room RM, and starts forced cooling at the point when it is detected by the person-detection unit 12 that a person exists near the entrance.

With this, the background temperature Tb near the entrance is constantly lowered, so there is constantly a temperature difference with the surface temperature of a person, and the presence or absence of a person is accurately detected by the person-detection unit 12. Therefore, forced cooling of the entire room RM is started at the point when the existence of a person near the entrances is confirmed, so it is possible to circumvent wastefully implementing forced air conditioning even when there is no person in the room RM.

[Expansion of the Embodiments]

Above, the present invention was described by way of reference to embodiments. The present invention is not to be construed to be limited thereto. A variety of modifications that can be understood by persons skilled in the art within the scope of the present invention can be applied to its constitution and details. Furthermore, each of the embodiments described above can be freely combined within the scope for which there is no inconsistency.

EXPLANATION OF CODES

A1, A2 Area

10 Air-conditioning control apparatus

11 Thermal-image generation unit

12 Person-detection unit

13 Background-temperature calculation unit

14 Air-conditioning control unit

20 Air-conditioning equipment

21, 22, 23, 24 Air-conditioner

31, 32 Lighting fixture

S1, S2 Temperature sensor

RM Room

L1, L2, L3 Communication line 

1. An air-conditioning control apparatus comprising: a person-detection unit that detects the presence or absence of a person in a room based on a thermal image of the room generated from data outputted from temperature sensors arranged in the room RM that is targeted for control; an air-conditioning control unit that implements air-conditioning control of the room based on person-detection results obtained by the person-detection unit; and a background-temperature calculation unit that calculates the background temperature that relates to the background region in the background of a person from the thermal images, wherein the air-conditioning control unit compares the judgment temperature for judging whether it is necessary to start forced cooling in the room and the background temperature, and starts forced cooling to lower the background temperature at the point when the background temperature is above the judgment temperature.
 2. The air-conditioning apparatus according to claim 1, wherein the person-detection unit includes a low-precision person detection function that searches for a person region that indicates the surface temperature of a person from the thermal images, and detects the presence or absence of a person based on the search result, and a high-precision person detection function that detects the presence or the absence of a person based on the presence or absence of movement in the person region searched in each of the thermal images accumulated in time series, and the air-conditioning control unit instructs the person-detection unit to switch to the high-precision person detection function at a point when the background temperature is higher than the judgment temperature, and to start forced cooling at a point when the existence of a person is detected by the person-detection function.
 3. The air-conditioning apparatus according to claim 1, wherein the air-conditioning control unit starts forced cooling when the background temperature is higher than the judgment temperature, and it is also notified from outside that a person has entered the room.
 4. The air-conditioning apparatus according to claim 1, wherein the air-conditioning control unit constantly implements partial cooling to lower the background temperature near an entrance of the room, and starts forced cooling at a point when the existence of a person is detected by the person-detection unit near the entrance.
 5. The air-conditioning apparatus according to claim 1, wherein the air-conditioning control unit partially cools a region where the background temperature in a room is higher than the judgment temperature as forced cooling.
 6. An air-conditioning control method comprising: a person-detection step that detects the presence or absence of a person in a room based on a thermal image of the room generated from data outputted from temperature sensors arranged in the room that is targeted for control; an air-conditioning control step that implements air-conditioning control of the room based on person-detection results obtained by the person-detection step; and a background-temperature calculation step that calculates the background temperature that relates to the background region in the background of a person from the thermal images, wherein the air-conditioning control step compares the judgment temperature for judging whether it is necessary to start forced cooling in the room and the background temperature, and starts forced cooling to lower the background temperature at the point when the background temperature is above the judgment temperature. 